Passive Quenching Sacks for Battery Thermal Runaway Containment
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Solution Overview
Problem
Current thermal management systems for battery assemblies in electric vehicles rely on active cooling methods that require sensors and controllers, which can be energy-intensive and prone to delays in thermal runaway mitigation, and do not effectively prevent thermal propagation between cells.
Innovation Solution
A passive thermal management system using dielectric coolant-containing bags with thermomechanical plugs that open at a predefined temperature to release coolant directly into battery cells, providing immediate cooling without the need for active sensing or controllers, and enhancing cooling efficiency by reducing cell-to-cell thermal propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active cooling methods with sensors and controllers are used, then temperature regulation capability is improved, but energy consumption increases and response delay occurs
Solution Approach 1:
The thermal management system utilizes the thermal runaway process itself to activate the cooling mechanism. When a battery cell experiences thermal runaway and its temperature rises, the heat directly melts the thermomechanical plugs, which in turn activates the coolant discharge. This self-activating mechanism eliminates the need for external sensors and controllers, thereby reducing energy consumption while maintaining effective temperature regulation.
Solution Approach 2:
The system employs phase transition of the thermomechanical plugs (from solid to liquid or from structured to disintegrated state) as a temperature-dependent trigger mechanism. The plugs are designed to melt or disintegrate at a predefined temperature threshold, automatically initiating coolant flow into the affected battery cell. This phase transition-based activation provides responsive temperature control without requiring active sensing or control systems.
2Temperature
If active cooling methods with sensors and controllers are used, then temperature regulation capability is improved, but response time deteriorates due to delays in thermal runaway mitigation
Solution Approach 1:
The system performs preliminary preparation by pre-positioning the coolant bags adjacent to each battery cell and pre-setting the thermomechanical plugs at the fluid ports. All components are ready in advance, with the coolant already positioned for immediate discharge. When thermal runaway occurs, the pre-positioned system activates instantly through the thermomechanical plug response, eliminating the time delay associated with sensor detection and controller activation in traditional active cooling systems.
Solution Approach 2:
The invention replaces the electronic sensing and control system with a direct thermal-mechanical response system. Instead of using sensors to detect temperature and controllers to activate cooling, the system uses the thermal energy from thermal runaway itself to mechanically trigger the cooling mechanism through thermomechanical plug melting. This substitution eliminates the sequential delays inherent in electronic detection and control systems, achieving near-instantaneous response.
3Temperature
If active cooling methods are used, then temperature control is improved, but system complexity increases due to sensors and controllers
Solution Approach 1:
Each battery cell is equipped with its own coolant bag and thermomechanical plug system that autonomously activates when needed. The system serves itself by using the thermal runaway heat to trigger the cooling mechanism without external intervention. This distributed self-service approach simplifies the overall system architecture by eliminating the need for centralized sensors and controllers, reducing system complexity while maintaining effective temperature control.
Solution Approach 2:
The thermal management system is segmented into independent modular units, with each battery cell having its own dedicated coolant bag and thermomechanical plug assembly. This segmentation allows each cell to be managed independently, eliminating the need for complex centralized control systems. The modular design simplifies the overall system structure while enabling targeted cooling of affected cells without requiring system-wide control mechanisms.
4Temperature
If active cooling methods are used, then temperature control is improved, but reliability decreases due to susceptibility to delays in thermal runaway mitigation
Solution Approach 1:
The invention replaces the electronic sensing and control system with a direct thermal-mechanical response system. The thermomechanical plugs respond directly to thermal runaway heat through melting or disintegration, providing a fail-safe mechanism that does not depend on sensor functionality or controller operation. This mechanical substitution enhances reliability by eliminating potential failure points in the electronic control chain while maintaining effective temperature control.
Solution Approach 2:
The system incorporates redundant cooling capability through multiple coolant bags positioned adjacent to each battery cell. If one cooling mechanism fails or is insufficient, adjacent coolant bags provide backup cooling capacity. This beforehand cushioning approach ensures that the system maintains reliability even if individual components fail, as the passive thermal response and multiple coolant sources provide a margin of safety against thermal runaway propagation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The passive system effectively prevents thermal runaway by immediately activating cooling when needed, reducing energy release to the cell solid, minimizing gas temperatures, and increasing battery capacity, leading to improved vehicle efficiency and driving range.
Implementation Method 1
A passive thermal management system with one or more dielectric coolant-containing bags that passively activate to quench cylindrical or prismatic lithium-class battery cells
Implementation Method 2
A passive thermal management system with one or more dielectric coolant-containing bags that passively activate to quench cylindrical or prismatic lithium-class battery cells
Implementation Method 3
direct-conduction liquid dielectric coolant
Implementation Method 4
the coolant absorbs thermal energy at the cell initiation area of a TR event
Implementation Method 5
A passive thermal management system with one or more dielectric coolant-containing bags that passively activate to quench cylindrical or prismatic lithium-class battery cells
Data Source
AI summary
Presented are thermal management systems with passive quenching sacks for cooling battery assemblies, methods for making/using such systems, and vehicles equipped with such systems. A passive thermal management (PTM) system is presented for cooling a battery assembly, such as a traction battery pack with a battery case containing stacked battery cells. The PTM system includes a fluid container that mounts inside the battery assembly, interposed between the battery case and battery cells. The fluid container stows therein a dielectric coolant fluid and has multiple fluid ports that fluidly connect to the battery cells to dispense thereto the coolant fluid. Thermomechanical plugs, such as wax, film, or smart-material barriers, seal the fluid container ports and passively open (e.g., melt, bend, disintegrate, expand, etc.) at a predefined temperature to thereby unseal the fluid ports such that the coolant fluid is fed from the fluid container into the battery cells.